CRISPR-Cas13 Precision Transcriptome Engineering in Cancer.

The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated genes (Cas) system has been rapidly harnessed to perform various genomic engineering tasks. Recently, it has been demonstrated that a novel RNA-targeting CRISPR effector protein, called Cas13, binds and cleaves RNA rather than DNA substrates analogously to the eukaryotic RNA interference system. The known Cas13a-Cas13d effectors are able to efficiently cleave complementary target single-stranded RNAs, which represent a potentially safer alternative to deoxyribonuclease Cas9, because it induces loss-of-function phenotypes without genomic loss of the targeted gene. Furthermore, through the improvement in Cas13 effector functionalities, a system called REPAIR has been developed to edit full-length transcripts containing pathogenic mutations, thus providing a promising opportunity for precise base editing. Moreover, advanced engineering of this CRISPR effector also permits nucleic acid detection, allowing the identification of mutations in cell-free tumor DNA through a platform termed Specific High Sensitivity Enzymatic Reporter Unlocking. All of these properties give us a glimpse about the potential of the CRISPR toolkit for precise transcriptome engineering, possibly leading to an expansion of CRISPR technologies for cancer therapeutics and diagnostics. Here, we examine previously unaddressed aspects of the CRISPR-based RNA-targeting approach as a feasible strategy for globally interrogating gene function in cancer in a programmable manner. Cancer Res; 78(15); 4107-13. ©2018 AACR. ©2018 American Association for Cancer Research.